Zoledronic acid enhances tumor growth and metastatic spread in a mouse model of jaw osteosarcoma

OBJECTIVES

Investigation of the therapeutic effect of zoledronic acid (ZA) in a preclinical model of jaw osteosarcoma (JO).

MATERIALS AND METHODS

The effect of 100 μg/kg ZA administered twice a week was assessed in a xenogenic mouse model of JO. The clinical (tumor growth, development of lung metastasis), radiological (bone microarchitecture by micro-CT analysis), and molecular and immunohistochemical (TRAP, RANK/RANKL, VEGF, and CD146) parameters were investigated.

RESULTS

Animals receiving ZA exhibited an increased tumor volume compared with nontreated animals (71.3 ± 14.3 mm3 vs. 51.9 ± 19.9 mm3 at D14, respectively; p = 0.06) as well as increased numbers of lung metastases (mean 4.88 ± 4.45 vs. 0.50 ± 1.07 metastases, respectively; p = 0.02). ZA protected mandibular bone against tumor osteolysis (mean bone volume of 12.81 ± 0.53 mm3 in the ZA group vs. 11.55 ± 1.18 mm3 in the control group; p = 0.01). ZA induced a nonsignificant decrease in mRNA expression of the osteoclastic marker TRAP and an increase in RANK/RANKL bone remodeling markers.

CONCLUSION

The use of bisphosphonates in the therapeutic strategy for JO should be further explored, as should the role of bone resorption in the pathophysiology of the disease.

Mandibular Chondroblastic Osteosarcoma: A Case Report

Osteosarcoma is primarily a long-bone disease that rarely affects the facial bones. Chondroblastic osteosarcoma is a subvariant of osteosarcoma. Its defining characteristics include the presence of malignant spindle and polygonal cells, as well as a thick layer of chondroid matrix and interwoven neoplastic tissue deposition. Mandibular chondroblastic osteosarcoma, in particular, is often overlooked and disregarded as a presumptive diagnosis at the time of initial presentation. This is mainly because of its rarity or inadequate lesion evaluation. Here, we present the case of a 47-year-old female patient with a rapidly growing swelling at the anterior mandible that was initially misdiagnosed as an ossifying fibroma of the mandible. The subsequent histopathological examination confirmed the diagnosis of chondroblastic osteosarcoma of the mandible. The patient requested a more extensive and aggressive excision, with the possibility of adjuvant radiation or chemotherapy. This article illustrates a rare case of mandibular chondroblastic osteosarcoma, with a focus on the clinical and pathological features of the tumor that should be taken into account when making a differential diagnosis for oral bone lesions.

Clinical significance of adjuvant therapy after radical surgery for primary osteosarcoma of the jaws

BACKGROUND

Osteosarcoma of the jaw is one of the rare malignancies and the role of postoperative adjuvant therapy is unclear. This study explored the efficacy of adjuvant therapy after radical surgery for primary osteosarcoma of the jaw.

METHODS

The data were retrospectively analyzed from May 2012 to June 2021. The recurrence rate, disease-free survival (DFS) and 5‑year overall survival (OS) rate were calculated by Kaplan-Meier method. Intergroup rates were examined by chi-square test.

RESULTS

125 post-radical surgery patients were included. The median follow-up time was 66 months. Forty five cases suffered recurrence. The recurrence rate was 36.0%, and the 5‑year OS rate was 68.8%. In the adjuvant treatment group, twenty eight of 99 patients experienced disease progression. In the surgical treatment alone group, seventeen of 26 patients experienced disease progression. The recurrence rates in the two groups were 28.3 and 65.4%, respectively (χ2 = 12.303, p < 0.001). The 5‑year OS rate was 75.8 and 42.3%, respectively (χ2 = 10.734, p = 0.001). The median DFS of the relapse patients was 15.1 months (95% CI:13.00-17.20 months), and the 5‑year OS rate was 40.0%. Among them, 28 patients received adjuvant therapy while 17 received surgical treatment alone. The median DFS was 15.7 and 11.5 months, respectively, p = 0.024. The median OS was 69.6 months (95% CI 55.69 ~ 83.51 months) and 62.4 months (95% CI 49.06 ~ 75.74 months), respectively(p = 0.034).

CONCLUSION

Adjuvant therapy is one of the effective measures to reduce the relapse rate and improve OS after radical surgery for primary osteosarcoma of the jaw.

Current topics and management of head and neck sarcomas

Given the low incidence, variety of histological types, and heterogeneous biological features of head and neck sarcomas, there is limited high-quality evidence available to head and neck oncologists. For resectable sarcomas, surgical resection followed by radiotherapy is the principle of local treatment, and perioperative chemotherapy is considered for chemotherapy-sensitive sarcomas. They often originate in anatomical border areas such as the skull base and mediastinum, and they require a multidisciplinary treatment approach considering functional and cosmetic impairment. Moreover, head and neck sarcomas may exhibit different behaviour and characteristics than sarcomas of other areas. In recent years, the molecular biological features of sarcomas have been used for the pathological diagnosis and development of novel agents. This review describes the historical background and recent topics that head and neck oncologists should know about this rare tumour from the following five perspectives: (i) epidemiology and general characteristics of head and neck sarcomas; (ii) changes in histopathological diagnosis in the genomic era; (iii) current standard treatment by histological type and clinical questions specific to head and neck; (iv) new drugs for advanced and metastatic soft tissue sarcomas; and (v) proton and carbon ion radiotherapy for head and neck sarcomas.

[Rare cancers of the head and neck on behalf of the REFCOR, part 2]

Among the 16,000 new cases of malignant tumors of the head and neck diagnosed in France each year, 10% are not conventional squamous cell carcinomas. These so-called rare cancers are distinguished by their presentation and patterns of failure, which is important to recognize in order to offer specific adapted management and maximize the chances of tumor control. These cancers can be rare by their histology as well as their anatomical location when arising from the paranasal sinuses, salivary glands and ear. The management of these heterogeneous rare diseases of complex treatment has considerably been structured over the last 15 years, in particular via the French ENT Cancer Expertise Network (REFCOR) and international networks and registries (EURACAN, etc.). Structuration also favors research with identification of new entities and setting up of specific therapeutic trials. A first article (part 1) discusses the diagnostic and therapeutic specificities of these rare cancers, and develops the recommendations of the REFCOR concerning rare epithelial tumors, i.e., salivary tumors, sinonasal tumors, variants of conventional squamous cell carcinomas, neuroendocrine carcinomas, malignant odontogenic tumors, and ear tumors. This second article (part 2) is focused on non-epithelial tumors (sarcomas, mucosal melanomas, lymphomas, tumors of uncertain or undetermined malignancy) and describes the organization and missions of the REFCOR.

Characterization of the Tumor Microenvironment in Jaw Osteosarcomas, towards Prognostic Markers and New Therapeutic Targets

Background-The purpose of this study was to investigate the bone resorption, as well as the vascular and immune microenvironment, of jaw osteosarcomas (JO) and to correlate these features with patient clinical outcomes. Methods-We studied 50 JO biopsy samples by immunohistochemical analysis of tissue microarrays (TMAs). We investigated the bone remodeling markers RANK/RANKL/OPG, the endothelial glycoprotein CD146, and biomarkers of the immune environment (CD163 and CD68 of macrophages, CD4+ and CD8+ of tumor-infiltrating lymphocytes (TILs), and an immune checkpoint PD-1/PD-L1). The biomarkers were analyzed for their influence on progression (recurrence and metastasis), overall survival (OS), and disease-free survival (DFS). Results-A strong and significant correlation has been found between CD163 staining and lower OS and DFS. The level of CD4+ and CD8+ staining was low and non-significantly associated with survival outcomes. High levels of RANK and RANKL were found in the tumor samples and correlated with lower DFS. Conclusion-Our findings suggest that CD163+ TAMs represent markers of poor prognosis in JO. Targeting TAMs could represent a valuable therapeutic strategy in JO.

Systematic review of craniofacial osteosarcoma regarding different clinical, therapeutic and prognostic parameters

Background

Osteosarcomas are the most common primary bone tumor while occurrence in the craniofacial skeleton is relatively rare. There are clinical differences of osteosarcomas regarding their location. In this regard craniofacial osteosarcomas (COS) have special characteristics. Extracranial osteosarcomas (EOS) occur mainly in the long bones of the extremities (tibia, humerus and femur). These tumors metastasize hematogenically at a very early stage. In comparison, COS are mainly localized in the mandible and maxilla, occur later in life and show significantly less and later metastasis and respond differently to adjuvant therapy. In the literature, clinical characteristics of COS and EOS are rarely compared directly. The aim of this systematic review is to answer the question whether COS and EOS exhibit fundamentally different clinical behavior and how they differ in terms of survival rates and response to different therapies.

Methods

A systemic review was performed. Pubmed, Cochrane and Google Scholar were used as search engines. The literature research was done by using clearly defined terms and their links. 124 full texts were selected and evaluated for this review. The inclusion criteria were determined using the PICO model.

Results

COS have significantly better survival rates, especially if they are located in the jawbone. Surgical R0 resection is crucial for therapeutic success. The study situation regarding the benefit of neoadjuvant chemotherapy in COS is very inhomogeneous. There is also no evidence for the benefit of adjuvant radio- or chemotherapy in COS. The large heterogeneity of the studies in terms of therapeutic concept, initial situation of the patients and outcome considered, as well as the small number of patients with craniofacial osteosarcoma were limiting factors.

Conclusion

The results of this study show the clear therapeutic and prognostic differences between COS and EOS and underline the necessity to consider both types of osteosarcoma as independent tumor entities in future studies. Furthermore, the study highlights the importance of surgical R0 resection for the prognosis of COS patients. There is no evidence for therapeutic benefit of adjuvant/neoadjuvant radio-/chemotherapy in R0 resected COS cases.

Internal Jugular Venous Extension of a Mandibular Osteosarcoma With Literature Review

Head and neck osteosarcomas (HNOS) account for less than 1% of all head and neck cancers and makeup 6-10% of all primary osteosarcomas. Mandibular osteosarcomas are the second most common subtype of HNOS. They demonstrate higher recurrence rates; however, are amenable to surgery. An 18-year-old male presented with a 2 cm x 3 cm x 2 cm intraoral mass for two months. Biopsy revealed chondroblastic osteosarcoma. Computed tomography revealed extension into the left internal jugular vein. Composite resection of the left mandible, floor of the mouth, ventral tongue, submandibular gland, and modified radical neck dissection with fibular flap repair was performed. Adjuvant chemotherapy and palliative radiotherapy were added. Unfortunately, progressive metastasis to the contralateral mandible and entire spinal cord ensued. We report the first case of head and neck osteosarcoma with intravascular invasion into the internal jugular vein.

Advances in targeted therapy for osteosarcoma based on molecular classification

Osteosarcoma, a highly malignant tumor, is characterized by widespread and recurrent chromosomal and genetic abnormalities. In recent years, a number of elaborated sequencing analyses have made it possible to cluster the osteosarcoma based on the identification of candidate driver genes and develop targeted therapy. Here, we reviewed recent next-generation genome sequencing studies and advances in targeted therapies for osteosarcoma based on molecular classification. First, we stratified osteosarcomas into ten molecular subtypes based on genetic changes. And we analyzed potential targeted therapies for osteosarcoma based on the identified molecular subtypes. Finally, the development of targeted therapies for osteosarcoma investigated in clinical trials were further summarized and discussed. Therefore, we indicated the importance of molecular classification on the targeted therapy for osteosarcoma. And the stratification of patients based on the genetic characteristics of osteosarcoma will help to obtain a better therapeutic response to targeted therapies, bringing us closer to the era of personalized medicine.

Low-grade osteosarcoma is predominant in gnathic osteosarcomas: A report of seven cases of osteosarcoma of the jaw

OBJECTIVE

Primary osteosarcoma of the jaw bones is very rare, and histological features of gnathic osteosarcoma remain obscure. The purpose of this study was to describe the clinicopathological features of gnathic osteosarcoma.

MATERIALS AND METHODS

Seven cases of gnathic osteosarcoma from Japan diagnosed during the period between 2000 and 2016 were examined retrospectively. The histology of the surgical pathology materials was reviewed by two pathologists. Clinical information was obtained from the hospital's information system.

RESULTS

Of the seven cases, two patients had secondary osteosarcomas. As for the five cases of primary osteosarcoma, their ages ranged from 26 to 58 years (mean: 36.2, median: 28). Histologically, three cases were fibrotic tumors composed of spindle-shaped cells with mild to moderate nuclear atypia and the collagenous stroma accompanied by woven bones or mature lamellar-like bones. Two cases had cartilage formation. MDM2 and CDK4 expression was observed in two out of three cases on immunostaining. The histopathology of these three cases was regarded as the counterpart of low-grade osteosarcomas, namely, parosteal osteosarcoma and low-grade central osteosarcoma, arising in long bones.

CONCLUSIONS

The surprisingly high incidence (60%, 3/5 cases) of low-grade osteosarcoma explains the reason why gnathic osteosarcomas present a more favorable prognosis than osteosarcomas arising in long bones. Furthermore, it provides insight into the tumorigenesis mechanism of low-grade osteosarcomas arising in the jaw and other sites.

Pediatric Malignant Mandibular Tumors: Personal Experience and Literature Options Discussion

INTRODUCTION

Mandibular defects reconstruction could result challenging in childhood, due to facial and mandibular growth patterns. For these reasons, the choice of the most suitable reconstructive option in pediatric patients, affected by mandibular malignancies, still objects of debate.

OBJECTIVE

The aim of our study was to compare our reconstructive schedules to the existing literature in order to give a personal contribute to the present panorama.

METHODS

We performed, in October 2019, a retrospective evaluation of pediatric patients treated for biopsy-proven mandibular malignancies at our Institute between January 2013 and December 2016. All of them received multimodal therapy in accordance with standard guidelines and their demographic, clinical, treatment, and outcome parameters were collected and analyzed.

RESULTS

We observed a shorter duration of surgery, a faster tracheostomy tube and feeding-tube removal, and a minor hospitalization in patients who received grafts transfer compared to those who underwent microsurgical mandibular reconstruction. After a 36-month period of follow-up, osteochondral grafts showed a pattern of growth similar to the mandibular epiphysis (condilylion-gonion linear and vertical ratio ranging to 0.96-1.03 and 1-1.02 at orthopantomogram, respectively). No bone consolidation delays and functional impairment were recorded.

CONCLUSIONS

Free flaps mandibular reconstruction in children needs to be better assessed and proximal fibular epiphyseal free flap indication might deserve further studies. Osteochondral grafts find indication for lateral defects, 50-55 mm in maximum length and located in the mandibular ramus, without massive teeth or soft tissue defect. Condyle involvement does not represent an absolute contraindication to rib graft use.

Osteosarcoma of the Jaws: A Literature Review

Osteosarcoma of the jaws (OSJ) is a relatively rare disease, accounting for between 2% and 10% of all cases of osteosarcoma. It is morphologically and radiologically identical to the trunk and extremity variant, but distinct in several crucial aspects. The lesion is characterized by sarcomatous cells which produce a variable amount of osteoid bone. It arises centrally within the bone and can be subdivided into osteoblastic, chondroblastic and fibroblastic subtype, depending on the predominant cell type. Radiographically, these tumors display a spectrum of bone changes from well-demarcated borders to lytic bone destruction with indefinite margins and variable cortical bone erosion or, in some cases, images of sclerotic bone. Therapeutic options for OSJ include surgery, chemotherapy and radiotherapy, which are employed according to age of the patient, histological classification and localization of the tumor. Today, there is no general consensus in the treatment guidelines for the OSJ though surgery represents the key to the treatment. The main prognostic factor deeply influencing the patient's prognosis remains the complete tumor resection with negative surgical margins. The aim of the present review is to describe state of the art regarding diagnostic and surgical treatment aspects of the primary osteosarcoma of the jaws.

Osteosarcoma of the jaws: An overview of the pathophysiological mechanisms

Osteosarcoma (OS) is the most common cancer of bone. Jaw osteosarcoma (JOS) is rare and it differs from long-bone OS (LBOS) in terms of the time of onset (two decades later), lower metastatic spread, and better survival. OS is characterized by the proliferation of osteoblastic precursor cells and the production of osteoid or immature bone. OS arises from a combination of genetic aberrations and a favourable microenvironment. This local microenvironment includes bone cells, blood vessels, stromal cells, and immune infiltrates, all of which may constitute potential targets for anti-cancer drugs. Differences in the clinical and biological behaviour of JOS versus LBOS are likely to at least in part be due to differences in the microenvironment between the two sites. The present review provides a brief overview of the known pathophysiological parameters involved in JOS.

Recent advance in patient-specific 3D printing templates in mandibular reconstruction

Patient-specific 3D printing template is used in mandibular defect reconstruction with multiple deficiencies. During the operation, the template can accurately transfer the preoperative design, assisting surgeons to complete the surgery with high efficiency and accuracy. The template design has been continuously improved to obtain good application for miscellaneous classification and description. This review attempted to preliminarily analyse and summarise recent advancements in personalized 3D printing templates in mandibular reconstruction from the aspects of functional classification, existing problems, improved strategies and post-surgery evaluation by reviewing studies and through our combined clinical work and experience on hundreds of reconstruction surgeries.

Downregulation of UBE2T can enhance the radiosensitivity of osteosarcoma in vitro and in vivo

Aim: To investigate the effect of UBE2T gene on radiotherapy for osteosarcoma. Materials & methods: Gene Expression Omnibus database, RT-qPCR and immunohistochemical analysis were performed. Cell proliferation and cell cycle experiments were conducted after knockdown of UBE2T. Cell scratch, reactive oxygen species production and apoptosis experiments were conducted after the combination of radiotherapy and UBE2T silencing. Then the xenograft mode was further conducted. Results: UBE2T was highly expressed in human osteosarcoma. Suppression of UBE2T inhibited osteosarcoma cell proliferation and induced cell cycle arrest at the G2/M phase. Downregulation of UBE2T combined with radiation can substantially inhibit clonal formation and migration, and promote apoptosis of osteosarcoma cells in vitro and in vivo. Conclusion: UBE2T downregulation can enhance the radiosensitivity of osteosarcoma in vitro and in vivo.

Jaw osteosarcoma models in mice: first description

BACKGROUND

Osteosarcoma (OS) is the most common cancer of bone. Jaw osteosarcoma (JOS) is rare and it differs from other OS in terms of the time of occurrence (two decades later) and better survival. The aim of our work was to develop and characterize specific mouse models of JOS.

METHODS

Syngenic and xenogenic models of JOS were developed in mice using mouse (MOS-J) and human (HOS1544) osteosarcoma cell lines, respectively. An orthotopic patient-derived xenograft model (PDX) was also developed from a mandibular biopsy. These models were characterized at the histological and micro-CT imaging levels, as well as in terms of tumor growth and metastatic spread.

RESULTS

Homogeneous tumor growth was observed in both the HOS1544 and the MOS-J JOS models by injection of 0.25 × 10⁶ and 0.50 × 10⁶ tumor cells, respectively, at perimandibular sites. Histological characterization of the tumors revealed features consistent with high grade conventional osteosarcoma, and the micro-CT analysis revealed both osteogenic and osteolytic lesions. Early metastasis was encountered at day 14 in the xenogenic model, while there were no metastatic lesions in the syngenic model and in the PDX models.

CONCLUSION

We describe the first animal model of JOS and its potential use for therapeutic applications. This model needs to be compared with the usual long-bone osteosarcoma models to investigate potential differences in the bone microenvironment.

Young Adult With Osteosarcoma of the Mandible and the Challenge in Management: Review of the Pediatric and Adult Literatures

Neoadjuvant chemotherapy for osteosarcoma of the jaw (OSJ) remains controversial despite being a standardized treatment in osteosarcoma of the long bones. We present a case of a 22-year-old male with OSJ and performed a retrospective systemic review of previously published literatures of OSJ. We identified 27 articles: 7% recommended neoadjuvant chemotherapy, 22% recommended adjuvant chemotherapy, 19% recommended both neoadjuvant and adjuvant chemotherapy, 33% recommended against chemotherapy and 19% stated the role of chemotherapy is unknown. The lack of consensus regarding the use of chemotherapy in OSJ, despite its benefits, demonstrates the need to establish a standardized algorithm for OSJ.

Chemotherapy in head and neck osteosarcoma: Adjuvant chemotherapy improves overall survival

BACKGROUND

Osteosarcoma is an aggressive bone malignancy presenting uncommonly in head and neck sites. Surgery is mainstay in treatment. However; trials show an improved survival with addition of chemotherapy in the treatment of extremity osteosarcoma. The head and neck osteosarcomas(HNOs) were excluded in these trials because of atypical presentation and disease course. Further; sufficient numbers were not possible for a trial. We present the largest retrospective study from single institute investigating the role of chemotherapy in the management of HNOs.

PATIENTS AND METHODS

The retrospective cohort of HNOs treated from 2007 to 2015 of a tertiary hospital were charted. The therapeutic and prognostic factors were analyzed for overall survival(OS), disease free survival(DFS), local control(LC) and metastasis(MT) in univariate and multivariate analysis. The minimum and median period of follow up was 12months and 56.04months respectively.

RESULTS

There was a total of 157 patients definitively treated with surgery in the time period. 7 patients had positive margins and all were maxillary or skull base tumors. The multivariate cox regression showed significance of tumor site(p=0.034), margin status (p=0.006), chemotherapy(p=0.025), histological subtype(p=0.012) as predictors of overall survival. The margin status(p=0.002), Radiotherapy(p=0.005) were significant predictors for local recurrence. The age and histology subtype(p=0.058) were borderline significant predictors of metastasis(p=0.065). The KM method for OS of different chemotherapy groups(p=0.013), and survival with and without chemotherapy(p=0.007) was significant. The OS was significantly better with adjuvant chemotherapy among various treatment plans(p=0.034).

CONCLUSION

Adjuvant chemotherapy improved OS while adjuvant radiotherapy improved local control of HNOs.

Distinctive Head and Neck Bone and Soft Tissue Neoplasms

Benign and malignant primary bone and soft tissue lesions of the head and neck are rare. The uncommon nature of these tumors, combined with the complex anatomy of the head and neck, pose diagnostic challenges to pathologists. This article describes the pertinent clinical, radiographic, and pathologic features of selected bone and soft tissue tumors involving the head and neck region, including angiofibroma, glomangiopericytoma, rhabdomyosarcoma, biphenotypic sinonasal sarcoma, chordoma, chondrosarcoma, and osteosarcoma. Emphasis is placed on key diagnostic pitfalls, differential diagnosis, and the importance of correlating clinical and radiographic information, particularly for tumors involving bone.

Impact of chemotherapy on the outcome of osteosarcoma of the head and neck in adults

Background

There is an ongoing debate about the value of (neo‐)adjuvant chemotherapy in high‐ and intermediate‐grade osteosarcoma of the head and neck.

Methods

All records of patients older than 16 years diagnosed with osteosarcoma of the head and neck in the Netherlands between 1993 and 2013 were reviewed.

Results

We identified a total of 77 patients with an osteosarcoma of the head and neck; the 5‐year overall survival (OS) was 55%. In 50 patients with surgically resected high‐ or intermediate‐grade osteosarcoma of the head and neck younger than 75 years, univariate and multivariable analysis, adjusting for age and resection margins, showed that patients who had not received chemotherapy had a significantly higher risk of local recurrence (hazard ratio [HR] = 3.78 and 3.66, respectively).

Conclusion

In patients younger than 75 years of age with surgically resected high‐ and intermediate‐grade osteosarcoma of the head and neck, treatment with (neo‐)adjuvant chemotherapy resulted in a significantly smaller risk of local recurrence. Therefore, we suggest (neo‐)adjuvant chemotherapy in patients amenable to chemotherapy. © 2016 The Authors Head & Neck Published by Wiley Periodicals, Inc. Head Neck39: 140–146, 2017

A new subtype of high-grade mandibular osteosarcoma with RASAL1/MDM2 amplification

In contrast to long bone osteosarcoma, mandibular osteosarcoma is highly heterogeneous and morphologically overlaps with benign tumors, obscuring diagnosis and treatment selection. Molecular characterization is difficult due to the paucity of available specimens of this rare disease. We aimed to characterize the spectrum of mandibular osteosarcoma using immunohistochemistry and molecular techniques (quantitative polymerase chain reaction and sequencing) and compare them with benign fibro-osseous lesions. Forty-nine paraffin-embedded mandible osteosarcoma tissue samples were collected retrospectively and compared with 10 fibrous dysplasia and 15 ossifying fibroma cases. These were analyzed for molecular markers thought to differ between the different diseases and subtypes: MDM2 (murine double-minute type 2) overexpression, GNAS (guanine nucleotide-binding protein/α subunit) mutations, and amplification of MDM2 and/or RASAL1 (RAS protein activator like 1). Five fibroblastic high-grade osteosarcoma subtypes showed MDM2 amplification, including 2 with a microscopic appearance of high-grade osteosarcoma with part low-grade osteosarcoma (differentiated/dedifferentiated osteosarcoma) and MDM2 overexpression. The other 3 contained a coamplification of MDM2 and RASAL1, a signature also described for juvenile ossifying fibroma, with no overexpression of MDM2. These were of the giant cell-rich high-grade osteosarcoma, with areas mimicking juvenile ossifying fibroma (ossifying fibroma-like osteosarcoma). Our results show that some diagnosed high-grade osteosarcomas are differentiated/dedifferentiated osteosarcomas and harbor an overexpression and amplification of MDM2. In addition, juvenile ossifying fibromas can potentially evolve into giant cell-rich high-grade osteosarcomas and are characterized by a RASAL1 amplification (osteosarcoma with juvenile ossifying fibroma-like genotype). Thus, the presence of a RASAL1 amplification in ossifying fibroma may indicate a requirement for closer follow-up and more aggressive management.

The Present and Future Opportunities of the Rare Cancer Network: An International Consortium for Advancement of Oncologic Care

To date, the Rare Cancer Network (RCN) has initiated more than 90 studies and 54 peer-reviewed publications were produced as a result. The Second International Symposium of the Rare Cancer Network recently took place in Istanbul, Turkey on April 17-18, 2015, and update was given on multiple currently ongoing projects, while also giving room for new proposals which will shape the direction of future studies for the group. This companion issue of the RCN Proceedings summarized the findings of this meeting, while also serving as a call for fresh projects and papers which will continue to energize the group and advance the oncologic science. A brief introduction to the principles, history, and vision of the RCN was also included. To review, the academic year of 2014-15 marked an enormous success for the international members of the RCN, with the generation of 8 fully published papers and more than 12 newly proposed topics. By the collective efforts of all RCN members, in the future, we look forward to the upcoming opportunities in continuing to advance the standard of chemo- and radiotherapeutic oncologic care for selected rare tumor topics. The studies of these rare cancers often do not allow the design and execution of prospectively enrolled trials; however, these uncommon malignancies do impact the humankind and add to its suffering globally in significant ways.

Chromosome 12 long arm rearrangement covering MDM2 and RASAL1 is associated with aggressive craniofacial juvenile ossifying fibroma and extracranial psammomatoid fibro-osseous lesions

To evaluate the diagnostic value of MDM2 status in craniofacial fibro-osseous lesions, we investigated MDM2 expression by immunohistochemistry and analyzed MDM2 amplification by qPCR in 30 cases of ossifying fibroma (including 13 cases of the juvenile variant) and 17 cases of fibrous dysplasia. Two cases of uncommon extragnathic psammomatoid fibrous dysplasia and a mixed control group of 15 cases of low-grade osteosarcoma and 15 cases of well-differentiated/dedifferentiated liposarcoma were included. MDM2 amplification was found in 33% of ossifying fibromas (peak of 69% for the juvenile variant) and in 12% of fibrous dysplasia, in none of which was MDM2 overexpressed. All control cases exhibited MDM2 amplification and overexpression. To investigate possible polysomy of chromosome 12, we studied RASAL1 amplification, a gene telomeric to MDM2 on the long arm of chromosome 12. RASAL1 amplification was reported in all benign fibro-osseous lesions exhibiting MDM2 amplification but not in controls. Simultaneous amplification of these two genes was significantly higher in juvenile ossifying fibromas compared with fibrous dysplasia (P=0.004), non-juvenile ossifying fibromas (P=0.001), and all other benign craniofacial fibro-osseous lesions combined (P=0.0001). Of the nine cases of juvenile ossifying fibroma exhibiting amplification, three were locally invasive and four were recurrent, suggesting aggressive disease. The two cases of extragnathic psammomatoid fibrous dysplasia also showed MDM2 and RASAL1 amplification with no MDM2 overexpression. This large chromosome 12 rearrangement, spanning MDM2 and RASAL1, is the first recurrent molecular abnormality to be reported in juvenile ossifying fibroma. It may represent both a molecular diagnostic marker and a characteristic of more aggressive forms with a higher risk of recurrence. Finally, the presence of this rearrangement in extragnathic psammomatoid fibro-osseous lesions mimicking ossifying fibromas might reflect a common molecular pathway in their pathogenesis and calls into question the classification of such lesions within fibrous dysplasia.

The rare cancer network: ongoing studies and future strategy

The Rare Cancer Network (RCN) was formed in the early 1990’s to create a global network that could pool knowledge and resources in the studies of rare malignancies whose infrequency prevented both their study with prospective clinical trials. To date, the RCN has initiated 74 studies resulting in 46 peer reviewed publications. The First International Symposium of the Rare Cancer Network took place in Nice in March of 2014. Status updates and proposals for new studies were heard for fifteen topics. Ongoing studies continue for cardiac sarcomas, thyroid cancers, glomus tumors, and adult medulloblastomas. New proposals were presented at the symposium for primary hepatic lymphoma, solitary fibrous tumors, Rosai-Dorfman disease, tumors of the ampulla of Vater, salivary gland tumors, anorectal melanoma, midline nuclear protein in testes carcinoma, pulmonary lymphoepithelioma-like carcinoma, adenoid cystic carcinoma of the trachea, osteosarcomas of the mandible, and extra-cranial hemangiopericytoma. This manuscript presents the abstracts of those proposals and updates on ongoing studies, as well a brief summary of the vision and future of the RCN.

Osteosarcoma in pediatric patients and young adults: a single institution retrospective review of presentation, therapy, and outcome

Background. Little is known about how cumulative chemotherapy delivery influences the poorer outcome observed in young adult (YA, 18–40 years) versus pediatric (<18 years) osteosarcoma patients. Here, we retrospectively examined differences in presentation, therapy, including cumulative chemotherapy dose, and outcome in YA and pediatric patients. Methods. We reviewed 111 cases of high-grade osteosarcoma at Moffitt Cancer Center between 1988 and 2012. Presentation factors, therapies, and survival were compared between YA and pediatric cohorts. Results. The cohorts were equivalent with respect to metastatic status, gender, tumor size, tumor site, and histological subtype. We found that the YA patients tended to have poorer histologic response to neoadjuvant chemotherapy measured by necrosis with 55% and 35% of pediatric versus YA patients responding favorably (P = 0.06). Only 39% of YA patients achieved the typical pediatric dose of methotrexate, doxorubicin, and cisplatin. These patients had a 3-year EFS of 76% (CI 53–100%) versus 47% (CI 26–69%; P = 0.09) in those who received less chemotherapy. Conclusion. Age continues to be a prognostic factor in osteosarcoma. Our study suggests that presentation factors are not associated with prognosis, while poorer response to chemotherapy and lower cumulative dose of chemotherapy delivered to YA patients may contribute to poorer outcomes.